Field of the Present Invention
The present invention relates generally to power cords and their connectors, and, in particular, to plug retention devices for electrical receptacles.
Background
Power cords are ubiquitous in the developed world, providing power from a conventional distribution system to electrically-powered devices of a very wide variety of types. Each power cord usually includes a cable with a plug or other electrical fitting at each end. For residential devices, most power cords utilize a plug having a standard size and arrangement of electrical connectors, with the particular standard being specific to a particular country or set of countries. Power cords for devices having electrical requirements that are different from that standard frequently utilize different sizes and/or arrangements to ensure that the wrong plug is not connected thereto.
In the computer industry, specialized plug/receptacle pairs are likewise used for various electrical needs. The plug/receptacle pairs are typically selected from conventional receptacle designs such as those set forward by IEC 60320. According to the standard, the specifications of corresponding female and male pairs of electrical connectors (such as C13 and C14 types) are defined such that the physical attributes of those connectors are standardized. By way of example, FIG. 1 is a front isometric view of a conventional female electrical receptacle. The illustrated receptacle is in the form of a panel-mount C13-type receptacle, but it will be appreciated that various other receptacle types with different electrical connection configurations also exist. The receptacle includes a female fitting surrounded by a socket. Female electrical contacts are contained within the female fitting. A plate may be provided on the front of, and typically integral with, the socket. The receptacle may be mounted in various fixtures using screws, solder joints, or in other known ways; the receptacle (and especially the socket) may include additional features to facilitate such mounting. The female electrical receptacle is adapted to receive a corresponding male electrical receptacle (not shown in FIG. 1). Such a male receptacle would typically include a male fitting from which male electrical contacts extend as well as a socket surrounding the male electrical contacts.
A common problem within the computer industry and without is the accidental dislocation of a particular plug (connector) from a receptacle. Because each plug commonly has a cord extending therefrom, it is easy to generate enough force, accidentally, to loosen the plug in the receptacle or even to pull it out entirely. Contributing to the problem is the fact that many connectors are designed to be removed easily by hand, which means that the force necessary to loosen or remove the plug is often not particularly great. The problem can be particularly vexing around power distribution units (PDUs).
As a result, many devices and techniques have been used to hold plugs in place. These include plugs that include threaded fittings (e.g., screws) that may be coupled to corresponding fittings on the receptacle, a retention element installed on the cord that can be attached to a stud or other element of the receptacle or PDU, bars or brackets fastened to the receptacle or PDU once the plug or plugs are in place, and the like. All of these have problems, from the need for special connector designs to their difficulty of use, particularly with regard to their ease of installation and removal. Thus, a need exists for a solution that does not require changes to the plug but which allows for easy installation and removal of the plug in and from a receptacle, while reliably holding the plug in place while installed.